The present invention relates to heavy duty lifting equipment and in particular to portable, hydraulically powered, reel jacks.
Various types of flexible cable and wire are supplied by being wrapped around large, heavy wooden spools or reels that have a central opening. When these spools or reels arrive at the job site filled with cable or sire to be consumed at the site, they may be rested on their circular edges on the ground or floor. In order to facilitate unwinding of the cable or wire from the reel or spool, the reel or spool desirably must be lifted off the ground or floor and rotatably carried on a rigid axle that allows the reel or spool to rotate as the cable or wire is pulled from the reel or spool. Thus, it is necessary for the workers to insert an axle through the central opening of the reel or spool. Opposite ends of the axle must be carried by a lifting mechanism that enables the axle to be elevated enough so that the reel or spool no longer touches the ground or floor and is free to rotate about the axle.
The reel or spool is a heavy object that becomes unstable when lifted off the ground or floor and thus poses a danger to the workers in the area. Many of the lifting mechanisms provide the lifting force in direct vertical alignment with the axis of rotation of the axle on which the reel or spool is carried. Because the workers operating the lifting mechanism must tend to stand alongside the lifting mechanism during its lifting and lowering operations, the workers may be struck if the axle becomes dislodged. Moreover, differently sized spools and reels require the height of the axle above the ground to be different in order to raise the reel or spool off the ground. Desirably, the lifting mechanism should move as little vertically as possible in order to effectuate the lifting of the reel or spool above the ground. In this way, the potential energy is minimized in the event of dislodgement of the axle and the extension of the lifting member also is minimized so that the stability of the lifting member is maximized.